HONEYWELL Y8735B1001 Communication Module. Consists of a W8735B Telephone Access Module and a CM8900 Communicating Module.
• Use with the PC8900/W8900 Perfect Climate Comfort Center. Provide remote telephone access to the HVAC system.
• CM8900 snaps into any new or existing W8900 module.
• W8735 Telephone Access Module plugs into the CM8900.
• Homeowners can call in-via touch-tone telephone and passcode to check the temperature, change the status of their home's system and perform other thermostat related functions.
• If there's an extended power outage, an extreme hot/cold temperature or other heating/cooling problem, the Telephone Access Module can call up to three pre-designated phone numbers.